The Tryptophanase from Escherichia coli K-12
نویسندگان
چکیده
منابع مشابه
Nucleotide sequence of the structural gene for tryptophanase of Escherichia coli K-12.
The tryptophanase structural gene, tnaA, of Escherichia coli K-12 was cloned and sequenced. The size, amino acid composition, and sequence of the protein predicted from the nucleotide sequence agree with protein structure data previously acquired by others for the tryptophanase of E. coli B. Physiological data indicated that the region controlling expression of tnaA was present in the cloned se...
متن کاملRole of leader peptide synthesis in tryptophanase operon expression in Escherichia coli K-12.
We used site-directed mutagenesis to replace the Escherichia coli tryptophanase (tna) operon leader peptide start codon with AUC. This change greatly decreased the uninduced rate of tna operon expression, and it also lowered the response to inducer. We conclude that leader peptide synthesis plays an essential role in tna operon expression.
متن کاملEvidence for transcription antitermination control of tryptophanase operon expression in Escherichia coli K-12.
Tryptophanase, encoded by the gene tnaA, is a catabolic enzyme distinct from the enzymes of tryptophan biosynthesis. Tryptophanase synthesis is induced by tryptophan and is subject to catabolite repression. We studied the mechanism of tna operon induction. Mutants with altered rho factor were partially constitutive for tna expression, implicating rho-dependent transcription termination in the c...
متن کاملEscherichia coli tryptophanase in the enteric environment.
The activity of the enzyme tryptophanase in the enteric environment was investigated to elucidate the significance of the enzyme in the metabolism of Escherichia coli. The tryptophanase activity, tryptophan content, and indole concentration as well as the numbers of E. coli were determined in the intestinal and fecal contents of conventional, germ-free, and monocontaminated axenic laboratory mi...
متن کاملEssential arginine residues in tryptophanase from Escherichia coli.
Tryptophanase from Escherichia coli B/1t7-A is inactivated by the arginine-specific reagent, phenylglyoxal, in potassium phosphate buffer at pH 7.8 AND 25 degrees. Apo- and holoenzyme are inactivated at the same rate, and inactivation of both is correlated with modification of 2 arginine residues/tryptophanase monomer. Substrate analogs having a carboxyl group protect the holoenzyme against bot...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1972
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)45594-4